The purpose of this work is to propose a new type of spin-valley locking (SVL), which can be called as C-paired SVL, in 2D antiferromagnetic systems. The methods include symmetry analysis and derivation for both piezomagnetism and spin current effect. Also, we use first-principle calculations to verify our theory in a 2D antiferromagnetic material. In the result of our work, C-paired SVL can exist without spin-orbit coupling(SOC), so it is different from normal SVL. The valleys are connected by crystalline symmetries, instead of time-reversal symmetry in normal SVL. The result also shows, a strong valley polarization can be introduced by simply breaking the corresponding crystalline symmetry, which can be used in multiple device applications. A strain field can induce large a n...[ Read more ]

The purpose of this work is to propose a new type of spin-valley locking (SVL), which can be called as C-paired SVL, in 2D antiferromagnetic systems. The methods include symmetry analysis and derivation for both piezomagnetism and spin current effect. Also, we use first-principle calculations to verify our theory in a 2D antiferromagnetic material. In the result of our work, C-paired SVL can exist without spin-orbit coupling(SOC), so it is different from normal SVL. The valleys are connected by crystalline symmetries, instead of time-reversal symmetry in normal SVL. The result also shows, a strong valley polarization can be introduced by simply breaking the corresponding crystalline symmetry, which can be used in multiple device applications. A strain field can induce large a net valley polarization/magnetization and a charge current can induce a large spin current. The first principle calculations of C-paired SVL in monolayer V₂Se₂O, show giant piezomagnetism and noncollinear spin current. The spin current in V₂Se₂O is about 5 ∼ 10 times larger than normal spin hall effect due to SOC. In conclusion, this work gives a chance to realize flexible controls of valley and spin for information encoding in single 2D materials through the piezomagnetism and noncollinear spin current effect in C-paired SVL, which is shown in the first principle calculations of V₂Se₂O.

KEY WORDS: Spin-valley locking, Crystalline symmetry, Piezomagnetism, Spin current.